Damage to anthropic elements estimation due to large slope instabilities through multi-temporal A-DInSAR analysis

Deep-seated gravitational slope deformations (DsGSDs) are widespread phenomena in the Alpine environment. Their dynamics, although very slow, endanger human settlements and connecting infrastructures. Monitoring such phenomena is mandatory to evaluate the impact on infrastructure networks and inhabited areas. Nowadays, the implementation of a tool useful to define and manage the interactions of DsGSDs evolution and the anthropic element remains a challenge, particularly in land use planning. Apart from on-site monitoring, which is commonly poorly used for DsGSDs observation, satellite-based interferometry represents the most comprehensive instrument for an effective spatial and temporal characterization of these phenomena. This paper provides a dedicated procedure to assess the usability of Advanced Differential Interferometric SAR (A-DInSAR) techniques to explore the DsGSDs behaviour and investigate their local interaction along anthropic elements. Combining multi-temporal A-DInSAR data, ERS-1/2 (1992–2000), Radarsat-1/2 (2003–2010), COSMO-SkyMed (2011–2018) and Sentinel-1 (2014–2018), over the Motta de Pletè and Champlas du Col DsGSDs, north-western Italy, a line-of-sight displacement investigation over a long-time span is implemented. Multi-temporal deformation maps are generated to define the deformation pattern and DsGSDs evolution over time. Subsequently, a local-scale analysis along the main anthropic elements is performed, exploiting Vslope values and ground deformation time series, integrated with ground-based ones, where available. This local analysis is aimed to recognize the most critical sections of the anthropic elements along with an higher level of damage, and potential risk is expected. Moreover, the obtained results are compared with a survey damage of the anthropic elements for a local cross-check and to strengthen the A-DInSAR methodology. Overall, the presented methodology provides a powerful tool to better define the DsGSDs local dynamics in correspondence of the main strategic infrastructures and inhabited areas, for a proper infrastructure maintenance and territorial planning strategy.